VITROS IMMUNODIAGNOSTIC PRODUCTS CORTISOL REAGENT PACK AND CALIBRATORS AND METABOLISM CONTROLS
Device Facts
| Record ID | K060480 |
|---|---|
| Device Name | VITROS IMMUNODIAGNOSTIC PRODUCTS CORTISOL REAGENT PACK AND CALIBRATORS AND METABOLISM CONTROLS |
| Applicant | Ortho-Clinical Diagnostics |
| Product Code | CGR · Clinical Chemistry |
| Decision Date | Jul 3, 2006 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 862.1205 |
| Device Class | Class 2 |
Indications for Use
VITROS Immunodiagnostic Cortisol Reagent Pack For the in vitro quantitative measurement of cortisol in human serum, plasma (heparin or EDTA) or urine. VITROS Immunodiagnostic Products Cortisol Calibrators For the in vitro use in the calibration of the VITROS Immunodiagnsotic System for the quantitative measurement of cortisol in human serum, plasma (heparin or EDTA) or urine. VITROS Immunodiagnostic Products Metabolism Controls For the in vitro use in monitoring the performance of the VITROS Immunodiagnostic System when used for the measurement of cortisol in human serum, plasma (heparin or EDTA) or urine.
Device Story
The VITROS Immunodiagnostic Cortisol Reagent Pack is an in vitro diagnostic assay used on the VITROS Immunodiagnostic System to measure cortisol concentration in human serum, plasma, or urine. The device utilizes a competitive immunoassay technique where cortisol in the sample competes with HRP-labeled cortisol conjugate for binding sites on a biotinylated sheep anti-cortisol polyclonal antibody. The complex is captured on coated microwells. A luminogenic substrate and electron transfer agent are added; HRP catalyzes light production, which is inversely proportional to the cortisol concentration. The system is operated by laboratory personnel in a clinical setting. The output is a quantitative cortisol concentration, which healthcare providers use to assess adrenal status. The device includes reagent packs, calibrators, and metabolism controls.
Clinical Evidence
Bench testing only. Performance was demonstrated using manufactured reagents, positive and negative controls, and testing of human samples throughout the assay range to confirm substantial equivalence to the predicate device.
Technological Characteristics
Solid-phase immunoassay using coated microwells. Detection via luminescence. Reagents include sheep polyclonal anti-cortisol antibody and enzyme-labeled tracer. Instrumentation: VITROS Immunodiagnostic System. Sample volume: 25µL. Incubation: 30 minutes at 37°C. Reportable range: 4.39 to 1700 nmol/L.
Indications for Use
Indicated for the quantitative measurement of cortisol in human serum, plasma (heparin or EDTA), or urine to aid in the assessment of adrenal status.
Regulatory Classification
Identification
A cortisol (hydrocortisone and hydroxycorticosterone) test system is a device intended to measure the cortisol hormones secreted by the adrenal gland in plasma and urine. Measurements of cortisol are used in the diagnosis and treatment of disorders of the adrenal gland.
Predicate Devices
- VITROS Immunodiagnostic Products Cortisol Assay (K983990)
Reference Devices
- VITROS Immunodiagnostic System (k962919)
- VITROS Immunodiagnostic Products Total T3 Reagent Pack and Calibrators (k964310)
- VITROS Immunodiagnostic Products Total β-hCG Reagent Pack and Calibrators (k970894)
Related Devices
- K983990 — VITROS IMMUNODIAGNOSTIC PRODUCTS CORTISOL ASSAY · Ortho-Clinical Diagnostics, Inc. · Dec 29, 1998
- K984520 — NICHOLS ADVANTAGE CHEMILUMINESCENCE CORTISOL IMMUNOASSAY, MODEL 62-7005 · Nichols Institute Diagnostics · Feb 5, 1999
- K021218 — ELECSYS CORTISOL TEST SYSTEM · Roche Diagnostics Corp. · Sep 9, 2002
Submission Summary (Full Text)
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY TEMPLATE
A. 510(k) Number:
k060480
B. Purpose for Submission:
Modifications to reagent pack
C. Measurand:
Cortisol
D. Type of Test:
Enzyme-linked Immunosorbent Assay (ELISA)
E. Applicant:
Ortho-Clinical Diagnostics
F. Proprietary and Established Names:
VITROS Immunodiagnostic Product Cortisol Reagent Pack
VITROS Immunodiagnostic Products Cortisol Calibrator
VITROS Immunodiagnostic Products Metabolism Controls
G. Regulatory Information:
| Product Code | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| CGR | II | 862.1205 | 75 |
| JIS | II | 862.1150 | 75 |
| JJX | I (reserved) | 862.1660 | 75 |
H. Intended Use:
1. Intended use(s):
See Indications For Use below.
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2. Indication(s) for use:
Device Name:
VITROS Immunodiagnostic Products Cortisol Reagent Pack
VITROS Immunodiagnostic Products Cortisol Calibrator
VITROS Immunodiagnostic Products Metabolism Controls
Indications for Use:
The measurement of cortisol in human serum, plasma (heparin or EDTA) or urine aids in the assessment of adrenal status.
3. Special conditions for use statement(s):
For prescription use only.
4. Special instrument requirements:
VITROS ECi/ECiQ Immunodiagnostic System
I. Device Description:
The VITROS Immunodiagnostic Cortisol Reagent Pack uses luminescence as the signal in the determination of cortisol concentration in serum, plasma, or urine. Coated microwells are used as the solid phase separation system. The system is comprised of three main elements:
- The VITROS Immunodiagnostic Products Cortisol Reagent Pack, VITROS Immunodiagnostic Products Cortisol Calibrators (cleared under k983990) and VITROS Immunodiagnostic Products Metabolism Controls (cleared under k983990), which are combined by the VITROS Immunodiagnostic System to perform the VITROS Cortisol assay.
- The VITROS Immunodiagnostic System – instrumentation, which provides automated use of the immunoassay kits. The VITROS Immunodiagnostic System was cleared for market by a separate 510(k) pre- market notification (k962919).
- Common reagents used by the VITROS System in each assay. The VITROS Immunodiagnostic Products Signal Reagent and VITROS Immunodiagnostic Products Universal Wash Reagent were cleared as part of the VITROS Immunodiagnostic Products Total T3 Reagent Pack and VITROS Immunodiagnostic Products Total T3 Calibrators 510(k) premarket notification (k964310).
Note: High Sample Diluent B was cleared as part of the VITROS Immunodiagnostic Products Total β-hCG Reagent Pack and VITROS Immunodiagnostic Products Total β-hCG Calibrators 510(k) premarket notification (k970894). The VITROS System and common reagents are dedicated specifically for use with the VITROS Immunodiagnostic Products range of immunoassay products.
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# J. Substantial Equivalence Information:
| Predicate | | k983990 VITROS Cortisol Assay | |
| --- | --- | --- | --- |
| Describe the item being compared | | | |
| The modified VITROS Immunodiagnostic Products Cortisol assay is substantially equivalent to VITROS Immunodiagnostic Products Cortisol assay previously cleared under k983990. The modifications to the assay only affect the VITROS Immunodiagnostic Products Cortisol Reagent Pack. There are no modifications to the current VITROS Immunodiagnostic Products Cortisol Calibrators or the VITROS Immunodiagnostic Products Metabolism Controls previously cleared under k983990. | | | |
| Similarites | | | |
| Device Characteristics | Predicate Device | | New Device |
| Sample type | serum, plasma (EDTA or heparin) and urine | | serum, plasma (EDTA or heparin) and urine |
| Basic principle | Solid phase immunoassay | | Solid phase immunoassay |
| Tracer | Enzyme labeled | | Enzyme labeled |
| Instrumentation | VITROS Immunodiagnostic System | | VITROS Immunodiagnostic System |
| Sample volume | 25 uL | | 25 uL |
| Incubation time and temperature | 30 minutes at 37 Celsius | | 30 minutes at 37 Celsius |
| Differences | | | |
| Device Characteristic | Predicate Device | | New Device |
| Biotinylated Antibody Reagent HRP Conjugate Reagent | Antibody Sheep polyclonal anti-cortisol antibody biotinylated antibody reagent (pool of two bleeds from a single sheep immunized in-house at Pollards Wood) Concentration 1.5 mg/Kg Contains Bovine Alpha Globulin | | Antibody Sheep polyclonal anti-cortisol antibody biotinylated antibody reagent (pool of eight bleeds from two sheep immunized in-house at Pollards Wood); Concentration 0.5 mg/Kg Remove Bovine Alpha Globulin; Add ANS (8-anilino-1-napthalenesulfonic acid) |
| Reportable Range | 0 to 1700 nmol/L | | 4.39 to 1700 nmol/L |
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K. Standard/Guidance Document Referenced (if applicable):
| STANDARDS |
| --- |
| Title and Reference Number |
| Interference Testing in Clinical Chemistry; Approved Guideline (CLSI EP 7-A) |
| Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline (CLSI EP09-A2) |
| Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline-Second Edition (CLSI EP5-A2) |
| How to Define and Determine Reference Intervals in the Clinical Laboratory; Approved Guideline - Second Edition (CLSI C28-A2) |
| Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline (CLSI EP6-A) |
| Protocols for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline (CLSI EP17-A) |
L. Test Principle:
A competitive immunoassay technique is used. This depends on competition between Cortisol present in the sample with a horseradish peroxidase (HRP)-labeled Cortisol conjugate for a limited number of binding sites on a biotinylated sheep anti-cortisol polyclonal antibody. The antigen-antibody complex is captured by streptavidin on the wells. Unbound materials are removed by washing.
A reagent containing luminogenic substrates (a luminol derivative and a peracid salt) and an electron transfer agent (a substituted acetanilide) is added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminol derivative, producing light. The electron transfer agent increases the level and duration of the light produced. The light signals are read by the VITROS Immunodiagnostic System. The amount of HRP conjugate bound is inversely proportional to the concentration of Cortisol present in the sample.
M. Performance Characteristics (if/when applicable):
1. Analytical performance:
a. Precision/Reproducibility:
Precision was evaluated following CLSI (formerly NCCLS) EP5-A2. Two replicates of each of 3 freeze-dried control sera were assayed on 2 separate occasions per day on at least 20 different days. An identical experiment was performed for urine (including the urine extraction pretreatment steps) to assess precision for urine samples. The experiments were performed using 2
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reagent lots on 2 different VITROS Immunodiagnostic Systems. Results are summarized below:
Conversion: $\mu \mathrm{g} / \mathrm{dL} = \mathrm{nmol} / \mathrm{L} \times 0.03625$
| Serum (nmol/L) | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Mean Cortisol Concentration | Within-run* | | Within-calibration** | | Within-lab*** | | # Observed |
| | | SD | CV (%) | SD | CV (%) | SD | CV (%) | |
| System 1 | 93.5 | 2.07 | 2.2 | 4.43 | 4.7 | 4.42 | 4.9 | 80 |
| | 259 | 4.41 | 1.7 | 10.9 | 4.2 | 11.3 | 4.5 | 80 |
| | 771 | 16.6 | 2.2 | 36.0 | 4.7 | 38.2 | 5.1 | 80 |
| System 2 | 84.1 | 1.86 | 2.2 | 2.81 | 3.3 | 3.33 | 3.8 | 80 |
| | 233 | 5.99 | 2.6 | 7.32 | 3.1 | 9.08 | 3.7 | 80 |
| | 668 | 11.9 | 1.8 | 19.9 | 3.0 | 28.2 | 4.0 | 80 |
| Urine (nmol/L) | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Mean Cortisol Concentration | Within-run* | | Within-calibration** | | Within-lab*** | | # Observed |
| | | SD | CV (%) | SD | CV (%) | SD | CV (%) | |
| System 1 | 106 | 19.3 | 18.2 | 25.7 | 24.2 | 24.3 | 22.9 | 92 |
| | 307 | 21.0 | 6.8 | 34.6 | 11.3 | 37.1 | 12.1 | 92 |
| | 767 | 137 | 17.9 | 159 | 20.7 | 156 | 20.3 | 92 |
| System 2 | 119 | 27.9 | 23.4 | 35.1 | 29.5 | 34.3 | 28.8 | 96 |
| | 363 | 42.0 | 11.6 | 48.4 | 13.3 | 51.4 | 14.2 | 96 |
| | 874 | 150 | 17.2 | 174 | 19.9 | 181 | 20.7 | 96 |
* Within-run (Repeatability): Within-run precision was determined using duplicate determinations.
** Within-calibration: Total within-calibration precision was determined using a single lot of reagent over a single calibration interval.
*** Within-lab: Total within-lab precision was estimated using a single reagent lot calibrated weekly.
b. Linearity/assay reportable range:
The measuring range of the VITROS Cortisol assay is $4.39\mathrm{nmol / L}$ to 1700 nmol/L. Linearity of the assay was evaluated using protocols based on CLSI (formerly NCCLS) EP6-A. Two plasma sample pools were prepared with Cortisol titers near zero and at the high end of the range. A Cortisol stock solution was prepared in methanol. The high pool (pool 11) was prepared by mixing donor samples with an additional spike of Cortisol. The low pool (pool 1) was prepared from charcoal stripped plasma. The low and high
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concentration pools were mixed to give 9 additional pools of intermediate concentrations. A minimum of six singleton determinations of each of the individual pools were made together with singleton determinations of the QC In-house Controls with each of the two Master Lots on two different VITROS Immunodiagnostic Systems. Results are summarized below.
| Pool Number | Calculated Concentration (nmol/L) | Mean Measured Concentration (nmol/L) | Calculated % Recovery |
| --- | --- | --- | --- |
| 11 | pooled | 2090* | - |
| 10 | 1880* | 1870* | 99.5 |
| 9 | 1670 | 1710 | 102.4 |
| 8 | 1460 | 1470 | 100.7 |
| 7 | 1250 | 1260 | 100.8 |
| 6 | 1050 | 1040 | 99.0 |
| 5 | 837 | 837 | 100.0 |
| 4 | 629 | 614 | 97.6 |
| 3 | 420 | 410 | 97.6 |
| 2 | 212 | 195 | 92.0 |
| 1 | pooled | 4.02 | - |
| Measured as a % of Calculated: Overall Mean (%) = | | | 98.8 |
* Extrapolated values – concentration greater than highest calibrator. The reference calibrators consist of seven levels (0, 14, 82, 659, 1267 and 1725 nmol/L) so a Master Curve is calibrated for each Master Lot up to 1725 nmol/L. The customer calibrators consist of three levels (0, 125 and 750 nmol/L) and recreate the lot specific Master Curve on the customer's instrument when a calibration is run.
c. Traceability, Stability, Expected values (controls, calibrators, or methods):
Both the Calibrators and Metabolism Controls are value-assigned by performing multiple determinations using several VITROS Immunodiagnostic Systems. The Calibrators are traceable to in-house reference calibrators, which have been value-assigned to correlate to samples measured by gas chromatography/mass spectrometry. The calibration and curve-shape for the VITROS Cortisol assay is defined by a set of Reference Calibrators in the Reference Calibration Curve (RCC).
There are two types of magnetic cards provided to the customer with every calibrator pack. These are the lot calibration card and the protocol card. The lot calibration card contains encoded data which is specific to a lot of reagents, for example the master calibration data. The protocol card contains encoded information that allows the System to process the assay associated with the calibrators, for example assay incubation times and sample volumes.
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The Reagent Packs and Calibrators were subjected to simulated transport conditions. The data in this report supported the stability of the VITROS Cortisol reagent pack and calibrators up to the Week 22 timepoint when stored at 2-8°C. Therefore a shelf life of 16 Weeks is claimed for the reagent pack and calibrator when stored at 2-8°C.
VITROS Cortisol Calibrators consist of three levels with nominal values of 0, 125 and 750 nmol/L cortisol. VITROS Metabolism controls consist of three levels with nominal values of 90, 250 and 750 nmol cortisol/L.
d. Detection limit:
The sponsor defined analytical sensitivity as the concentration calculated from the mean light unit minus two standard deviations of a sample containing no analyte, where 20 replicates were determined. The analytical sensitivity of this assay is 3 nmol/L.
The Limit of Quantitation (LoQ) was evaluated using five plasma pools spiked with cortisol resulting in concentrations of 4.39, 10.5, 17.2, 17.3 and 23.1 nmol/L. Ten consecutive replicates of the samples were performed twice. Three Master Lots and three VITROS Immunodiagnostic Systems were used during the study for at least three days using three different calibrations. Each run included singleton determination of the Calibrators and QC in-house controls. The lowest sample from the concentrations tested giving accurate precision (defined as CV < 15%) was 4.39 nmol/L. The LoQ for this assay is 4.39 nmol/L (the LoQ is the low end of the reportable range of the assay).
e. Analytical specificity:
Specificity of the VITROS Cortisol assay was evaluated by testing the following substances as recommended by CLSI (formerly NCCLS) Protocol EP7-A. They were found not to interfere (defined as bias <10%) with the assay at a cortisol concentration of 241 to 288 nmol/L (8.74 to 10.4 mg/dL). Interferent testing was conducted by preparing stock solutions of the interferent. The stock solution was added to the VITROS Metabolism Control, Level 2 with a nominal value of 250 nmol/L. The corresponding control pool was prepared by reconstituting the VITROS Metabolism Control, Level 2 with water or with water/solvent (at the same ratio as the test substance pool, but without the test substance). The analyte levels present in the control sample were established using the VITROS Cortisol assay on the VITROS Immunodiagnostic System.
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| Test Substance | Concentration Tested | Interference Less Than: (%) |
| --- | --- | --- |
| Azide | 1.5 mmol/L | 9.9 |
| Bilirubin | 1.71 mmol/L | 4.7 |
| Triolein | 33.9 mmol/L | 2.1 |
| Dipyrone | 3.00 mmol/L | 6.3 |
| Biotin (serum) | 0.040 μmol/L | -2.1 |
| Biotin (extracted urine) | 0.040 mmol/L | 0.7 |
To evaluate the cross reactivity of prednisolone, 11-deoxycortisol, cortisone, and corticosterone in the VITROS Cortisol assay, three determinations at each dilution were made and analyzed as a percent cross-reactivity at 50% of zero standard binding of cortisol compared with the concentration at 50% displacement for the cross-reactant. The cross-reactivity at 50% displacement is defined as the point where the reduction in signal corresponds to 50% of the signal achieved in the absence of analyte, shown as a percentage of the analyte concentration giving the same fall in signal. For the remaining cross-reactants, the mean value of three determinations was compared with the concentration of the cross-reactant used for the test:
| Cross-reactivity at 50% displacement | |
| --- | --- |
| Test Substance | % Cross Reactivity |
| Prednisolone | 26.8% |
| 11-Deoxycortisol | 0.95% |
| Corticosterone | 1.03% |
| Cortisone | 0.13% |
| Test Substance | Concentration Tested (nmol/L) | Mean sample value of cross reactant pool (nmol/L) (measurement of sample containing no cortisol) | Mean % Cross-reactivity |
| --- | --- | --- | --- |
| Estriol | 96685 | 4.84 | 0.006 |
| Fludrocortisone | 26281 | 1011 | 3.85 |
| Prednisone | 139509 | 106 | 0.076 |
| Testosterone | 346741 | 23.0 | 0.007 |
| Progesterone | 317965 | 1460 | 0.459 |
| 17-α-Hydroxyprogesterone | 151286 | 836 | 0.553 |
| β-Cortol | 135685 | 7.32 | 0.006 |
| β-Cortolone | 81855 | <3.00 | ND |
| Dexamethasone | 127389 | 310 | 0.244 |
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| Test Substance | Concentration Tested (nmol/L) | Mean sample value of cross reactant pool (nmol/L) (measurement of sample containing no cortisol) | Mean % Cross-reactivity |
| --- | --- | --- | --- |
| 11-β-Hydroxyprogesterone | 30257 | 761 | 2.52 |
| 6-α-Methylprednisolone | 26702 | 1585 | 5.94 |
| 11-Deoxycorticosterone | 86580 | 30.6 | 0.035 |
| Tetrahydrocortisol | 81855 | 131 | 0.159 |
| Topiramate | 2946000 | <3.00 | ND |
*ND = Not Detectable. Concentrations were below the analytical sensitivity of the assay, <3.00 nmol/L.
Hemoglobin caused the bias shown at the concentrations indicated in the table below:
| | Hemoglobin Concentration | Units = nmol/L | |
| --- | --- | --- | --- |
| | | Analyte Conc.* | Bias** |
| Hemoglobin | 0.062 mmol/L | 310 | 25 |
| Hemoglobin | 0.310 mmol/L | 310 | 136 |
* Average test concentration of replicate determinations using two different lots of reagent determined from twelve samples containing approximately 300 nmol cortisol/L
** Estimate of the average difference observed.
Azide at concentrations greater than or equal to 0.05% have also been shown to interfere with this assay.
f. Assay cut-off:
Not applicable.
2. Comparison studies:
a. Method comparison with predicate device:
A total of 214 banked serum samples and 100 urine samples were collected. There were no inclusion or exclusion criteria required for this testing. Each of the 214 serum samples and 100 urine samples were assayed in singleton on the VITROS Immunodiagnostic System. One VITROS Immunodiagnostic System and one lot of reagents were used to test the predicate. Two VITROS
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Immunodiagnostic Systems and two Master Lots were used to test the VITROS Cortisol assay. The claimed working range of the VITROS Cortisol Assay is 4.39 to 1700 nmol/L. The range of serum samples tested was 14.5 to 1370 nmol/L. The range of urine samples tested was 3.33 to 685 nmol/L.
Results were determined using linear regression and are summarized below.
Serum: VITROS Cortisol Assay = 0.986 * (predicate) - 14.2 nmol/L
Urine: VITROS Cortisol Assay = 0.798 * (predicate) - 22.03 nmol/L
## b. Matrix comparison:
Twelve fresh blood samples were drawn into heparin plasma, EDTA plasma and serum tubes. They were assayed on the day they were drawn, after 5 and 7 days storage at 2-8°C and after 4 weeks at -20 °C in order to demonstrate that serum results match plasma results. Results are summarized below.
| Study | Sample Range Tested (nmol/L) | Mean % Difference Against Serum | | Range of % Differences Against Serum | |
| --- | --- | --- | --- | --- | --- |
| | | Heparin | EDTA | Heparin | EDTA |
| Fresh Samples | 144 - 529 | 0.0 | -6.7 | -8.5 to 4.9 | -10.2 to -3.0 |
| Stored at 2-8 °C for 5 Days | 147 - 490 | 0.2 | -6.2 | -8.9 to 8.1 | -11.3 to -0.4 |
| Stored at 2-8 °C for 7 Days | 151 - 479 | -3.1 | -3.1 | -8.5 to 4.6 | -9.8 to 6.0 |
| Stored at -20 °C for 4 Weeks | 157 - 531 | -1.5 | -7.1 | -8.4 to 4.3 | -13.9 to -2.0 |
## 3. Clinical studies:
a. Clinical Sensitivity:
Not applicable.
b. Clinical specificity:
Not applicable.
c. Other clinical supportive data (when a. and b. are not applicable):
Not applicable.
## 4. Clinical cut-off:
Not applicable.
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5. Expected values/Reference range:
The serum expected ranges, 123 to 626 nmol/L (obtained from 100 samples) and 46.2 to 389 nmol/L (obtained from 100 samples), were obtained from the sera of apparently healthy patients sampled in the morning before 10:00 AM and in the evening after 5 PM, respectively. The urine expected range is 35.7 to 699 nmol cortisol/24 hours (obtained from 42 samples) was obtained from 24-hour urine samples collected from apparently healthy patients.
N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.
O. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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